giffords and her husband, former astronaut mark kelly have now launched their own campaign for tougher gun laws. capitalizing on the public outcry that followed december's mass shooting at an elementary school in newtown, connecticut. >> after 20 kids and six of their teachers were gunned down in their classrooms at sandy hook, we said, th time must be different. something needs to be done. we are simply two reasonable americans who have said enough. >> ifill: but at today's hearings, national rifle association vice president wayne lapierre pushed back insisting that the real solution to gun violence is to enforce existing laws. >> unfortunately, we've seen a dramatic collapse in federal gun prosecutions in recent years. overall in 2011, federal weapons prosecutions per capita were down 35% from their peak in the previous administration. that means violent felons, gang members and the mentally ill who possess firearms are not being prosecuted. and that's unacceptable. proposing more gun control laws, while failing to enforce the thousands we already have is not a serious solution to re